It is common practice, in the civilian field, to use convoys to transport large quantities of material from one point to another in a single journey, without having to make multiple round trips. These convoys are generally made up of a plurality of vehicles that follow one another.
Nevertheless, the establishment of civilian convoys is generally expensive, both in terms of equipment, because a large number of vehicles are necessary to transport the material, and in terms of human resources, since each vehicle must be driven by a driver.
It is also common, in the military field, to have a soldier followed by a moving platform carrying the soldier's equipment. The soldier and his platform thus constitute a convoy, led by the soldier.
Nevertheless, it is desirable for the moving platform to be able to follow the soldier autonomously.
To resolve these problems, it has been considered to robotize the follower vehicles of a convoy. To that end, vehicle guidance systems have been developed.
These guidance systems are suitable for guiding the vehicle that they equip such that it follows a leader, made up of the vehicle preceding said equipped vehicle, or the soldier. To that end, each guidance system generally comprises a system for localizing the leader, suitable for identifying the position of the leader relative to the equipped vehicle, and an automatic driving system for the equipped vehicle based on the position of the leader identified by the localization system.
Different types of localization systems are known. The satellite positioning system (GPS) is one type of non-localization system. This system comprises a GPS beacon carried by the leader. This system is, however, dependent on the reception quality of the GPS signal, which may be scrambled, and requires active communication (radio, optical, etc.) between the leader and the follower.
Localization systems are also known of the vision type, using a daytime and infrared camera, suitable for identifying the leader in the scene filmed by the camera. However, these systems have the drawback of not allowing the leader to be located at all times and under all lighting conditions. These systems also pose problems of following the leader, who must remain in the field of the camera to be able to be localized. Lastly, these systems are expensive.
Localization systems of the goniometer type are also known, which, using a radio beacon carried by the leader and a radio receiver carried by the follower vehicle, make it possible to determine the axis in which the leader is located relative to the follower. However, by not giving the distance from the leader to the follower, these systems only provide partial information on the location of the leader.
Localization systems of the LIDAR type are also known. These systems comprise a LIDAR carried by the follower vehicle, and which makes it possible to locate the leader in a plane, or in space. These systems are, however, expensive.
Lastly, a localization system of the wired sensor type is known from US 2010/0049374. This system comprises a wired sensor carried by the follower vehicle, the wired sensor comprising a cable, attached by one end to the leader, a winder for the cable, and a member for measuring the length of unwound cable. The system further comprises an angle measuring device formed by the cable with the axis of the vehicle. However, environmental parameters, such as the wind speed, can easily vary said angle, leading to an error in the localization of the leader. Furthermore, it is difficult to find angular sensors precise enough to localize the leader precisely.